Screen



(No Model.)

GQW. GROSS. SCREEN.

} Patented May 25,1897.

UNITED STATES ATENT FFIQE GEORGE IV. CROSS, OF PITTSTON, PENNSYLVANIA.

SCREEN.

SPECIFICATION forming part of Letters Patent N 0. 583,032, dated May 25,1897.

Applicatio filed October 1, 1896. Serial No. 607,550. (No model.)

To aZZ whom it may concern:

Be it known that I, GEORGEWV. CROSS, a citizen of the United States,residing at Pittston, in the county of Luzerne and State ofPennsylvania, have invented a certain new and useful Improvement inScreens, of which the following is a specification.

This invention relatesto screens for the separation of coal and similarmaterials into the various sizes. It concerns particularly that type ofscreening-surfaces in which the webs or bars bounding the intersticesare curved or crimped out of the plane of the working face. An exampleof this type is shown in Letters Patent No. 523,515, granted to me onJuly 24, 1894. In screens of the type described two importantconsiderations obtain. First, the surface must be so crimped as toprovide the maximum amount of strength or resistance to the wearing anddistorting efiect of the material being screened, and, second, provisionmust be made for facilitating the screening operationthat is to say, theparticles of material must be so treated as to readily find the mesh andpass through the interstices therein. In the present invention both ofthese main requirements are met, the result being a screeningsurface ofgreat strength, durability, and efficiency.

In carrying out the invention I employ an integral metallic plateprovided with sub-- stantially rectangular interstices, the latter beingstaggered in their arrangementthat is to say, each transverse webbetween the interstices of one longitudinal row being opposite aninterstice in the next adjacent rows. The longitudinal webs, whichextend continuously from end to end of the plate, are undulatory inform, each convexity in one web being opposite a concavity in the twoadjacent webs. The transverse Webs, which are separated owing to thestaggered relation of the interstices and which join the continuouslongitudinal webs, extend from the convexity of one of the latter to theconcavity of the next adjacent longitudinal Web. These transverse websare therefore inclined at an angle relatively to the plane of the plateand, what is more important, are not curved, but are straight from endto end. The first advantage obtained by this construction is maximumstrength. The primary object of all crimping is the agitating ortumbling of the material in its passage through the screen. This actionis obtained by moving the particles relatively to each other by means ofthe curved webs. It is the occasion of much dest-ructive wear upon thescreen-surface. especially such surfaces as are designed for theseparation of coal and stone, which are frequently called upon toseparate a continuous and heavy mass of material. In the constructionabove described that portion of the material next adjacent to thescreen-surface is guided into the interstices by the downwardly inclinedtransverse web bars, the lower ends of which join the continuouslongitudinal bars at the lowest point of the latter. On the oppositeside of the perforations the particles strike the convexities of thelongitudinal webs and are thereby interrupted and guided into theperforations bounded by those webs. The force of the blow is not bornewholly by the convexities referred to, as these are strengthened by theinclined transverse webs behind them and which support and sustain thelongitudinal webs to which they are joined at the highest points ofconvexity of the latter. In this manner the destructive feature of theagitating or tumbling operation is minimized. Another and equallyimportant advantage is the increased efficiency of the surface due tothe fact that the particles of material are guided to eachinterstice bymeans of the downwardly-inclined transverse web-bars, which form ineffect grooves terminating with the interstices. In addition to this theopposite side of each interstice to which particles have been guidedbeing above the plane at which the coal passes over the surfaceinterrupts its passage, and if the particles are of the proper sizeassures their passage through such interstices.

In the drawings, Figure 1 is a perspective view of a screen-segmentemploying my invention. Fig. 2 is a transverse section on the line 2 2,Fig. 1. Fig. 3 is a longitudinal section on the line 3 3, Fig. 1. Fig. 4is an enlarged sectional View on the line 4 4, Fig. 1; and Fig. 5 is anenlarged View in plan of a portion of the mesh or screening-surface ofthe segment shown in Fig. 1.

The invention has been illustrated as embodied in a screen plate orsegment forming part of the jacket of a revolving screen. It is to beunderstood, however, that the improved construction may with advantagebe employed in a continuous jacket or in plates for plane screens, suchas shaking or gyrating screens.

Referring to the drawings, in which simi lar letters of reference denotecorresponding parts, A designates a segment formed, preferably, ofsheet-steel and provided in this instance with imperforate end marginsto and imperforate side margins a (L This plate is provided withinterstices 13, substantially rectangular in form. It has been founddesirable in practice where rectangular interstices are used to roundthe corners for the purpose of contributing strength to the junctions ofthe webs. The interstices B are staggered relatively to each other,being in the present instance arranged continuously in longitudinalseries and alternately in transverse series.

The interstices B are bounded by continuous undulating longitudinal websb and by separated inclined transverse webs c. It will be noted that thelongitudinal webs are so arranged as that a convexity in one web shallbe opposite a concavity in the longitudinal webs 011 either side of it.

The separated transverse webs c extend between and connect the convexityof one longitudinal web and the concavity of the next adjacentlongitudinal web. Owing to this each transverse web is inclined at anangle relatively to the plane of the screen-surface.

In operation the material is fed upon the screen-surface, preferablyfrom the left in the present instance. Such particles as do not passthrough the first row of interstices slide downwardly upon the inclinedtransverse webs c, separating the interstices of the first row, over theconcave portions of the longitudinal webs Z) into an interstice l3.Should they be of sufiieient size to pass through said interstices, suchpassage is assured by the convexities bounding the other sides of theinterstices. Such particles as are not of the proper size to passthrough the interstices are interrupted and tumbled by the longitudinalconvexities, and the smaller particles, suitable for screening at thatportion of the surface, are permitted to pass through the interstices.Such particles of the proper dimensions to pass through the screen as donot pass through, for instance, the first or second row or rows ofperforations are guided, not only by the inclined transverse webs, butalso by the downward curvature of the convex portions of thelongitudinal webs, into the interstices of the next adjacent row. Theoperation is therefore continuous, the separation of the particles isgreatly facilitated, and the useful life of the surface as a whole isprolonged.

\Vhat I claim is l. A screen surface having interstices bounded bycontinuous, undulatory, longitudinal webs and separated, straight,transverse webs, substantially as set forth.

2. A screen-surface having substantially rectangular interstices, thetwo parallel sides of each interstice being one concave and the otherconvex, the other two sides being straight and inclined from end to end,relatively to the working face, substantially as set forth.

Ascreen-surface boundedbyundulatory, longitudinal webs, each convexityin one of said webs being opposite a concavity in the next adjacentlongitudinal web, and by straight, transverse webs extending between andconnecting the concavities in one of the longitudinal webs and theconvexities in the next adjacent longitudinal web,substantially as setforth.

This specification signed and witnessed this 30th day of September,1896.

GEORGE \V. CROSS.

Vitnesses:

S. O. EDMONDS, J NO. R. TAYLOR.

